This program of research seeks to increase scientific understanding of the role that beliefs and coping strategies play in temporomandibular disorder (TMD) patient adjustment, and to evaluate {{ the efficacy and underlying mechanisms of action of}} a brief {{cognitive-behavioral}} intervention designed to increase adaptive beliefs and coping strategy use, and decrease maladaptive beliefs. {{ Both observational and experimental methods will be used to test hypotheses derived from cognitive- behavioral theory concerning the relationships of beliefs and coping with pain intensity, activity interference, and mood. Electronic daily diary methodology will be used in a longitudinal study to assess temporal sequencing of relationships among patient beliefs, coping strategies, pain intensity, activity interference, and mood, within and across individuals before and during participation in a randomized clinical trial. Patients {{N=176}} who are seeking treatment for TMD at a specialty clinic {{and who have high levels of pain and activity interference}} will be assigned randomly to usual treatment plus a brief cognitive-behavioral intervention (UT + CBT) or to usual treatment {{plus an education and attention control (UT + Education).}} The effects of the cognitive- behavioral intervention on patient outcomes (pain intensity, activity interference, and mood) {{and on process variables (beliefs and coping) hypothesized to mediate outcomes}} will be assessed by questionnaire and daily diary measures from baseline to post-intervention, and by questionnaire measures at six and twelve month follow-ups. Data analyses will test the hypotheses that {{usual care plus the cognitive- behavioral intervention will result in greater short- and long-term improvement in TMD patient outcomes, as compared with usual care plus education and attention,}} and that improved outcomes in the UT + CBT group will be mediated by changes in patient beliefs and coping strategies. {{Additional analyses will test hypotheses concerning the temporal relationships among beliefs, coping, and patient outcomes.}} Thus, the proposed study will provide important information about (1) the temporal relationships among TMD patient beliefs, coping strategies, pain, and activity interference; (2) the efficacy of a brief cognitive- behavioral intervention integrated with usual treatment in a TMD clinic; and (3) specific beliefs and coping strategies that mediate improvement in patient pain and functioning and that therefore are important to target in treatment.